Overcoming the Internet Impasse through Virtualization

1
Overcoming the Internet Impasse through
Virtualization
Defense Chen, Jiazhen Teng, Xian Yi
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The problem we face

• Internets increasing ubiquity and centrality has
  brought with it a number of challenges for which
  the current architecture is ill-suited.
• To support new application
• Modifications have arisen to meet legitimate
  needs that the architecture itself could not.
• However, modification serve a valuable short-term
  purpose
• But impair the long-term flexibility, reliability
  and manageability.

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The Impasse

• Since the current architecture is not well suited
  to nowadays application.
• WHY NOT Design a new one?
• The Impasse
• Persuade ISPs to adopt a new architecture
• Traditional test-beds have limitations.

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Our Goal

• To issue a call to ACTION!
• Cease being satisfied with paper design that
  have no future.
• Overcome the Impasse.
• To reduce the barrier to evaluate new idea in
  architectural design.
• How to make a test that simulates the reality?

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How to OVERCOME

• 3 separate requirements
• Easily experiment with new architectures on live
  traffic
• A plausible deployment path s. t. design can come
  into practice.
• Comprehensively proposed architectural solutions
• To meet these requirements
• We propose a Virtual Test-bed

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Virtualization

• A high level abstraction that hides the
  underlying implementation details.
• Let node treat an overlay as if it were the
  native network
• Multiple overlays are simultaneously used
• This approach does not require universal
  architectural agreement
• More plausible deployment.

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Limitations of current approaches

• Two ways in which researchers currently
  experiment with new architecture
• Physical Test-beds
• Overlays

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Limitations of Physical Test-beds

• Production-oriented Testbed
• The users have no choice about whether or not to
  participate in the testbed
• Research Testbed
• Driven by synthetically generated traffic
• Both utilize dedicated transmission links
• Involve substantial cost.

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Limitations of Overlays

• Advantages
• Not limited geographically
• Usage is voluntary
• Not involve significant expenditure
• Drawbacks
• Overlays have been seen as a way of deploying
  narrow fixes to specific problems
• Overlays have been architecturally tame, most
  typically assume IP as the architecture inside
  the overlay itself
• No dramatic architectural advancement

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Virtual Testbed

• Two basic components
• Substrate Overlay
• Set of dedicated but multiplexed overlay nodes
• Amortized by concurrently running experiments
• Drastically lower the barrier-to-entry for
  individual researcher.
• General Client-proxy mechanism
• Allows any host to opt-in to a particular
  experiment
• Treats nearby overlay node as the hosts
  first-hop router
• Not require IP addressing
• Multiplexed substrate overlay and general proxy
  solve the barrier-to-entry and architectural
  limitations.

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Virtual Testbed - 2

• However there are issues to explore
• To achieve sufficiently high throughput rates on
  PlanetLab nodes.
• The packet forwarding capability of nodes has
  physical limitation.
• New designed architecture may purpose to achieve
  higher throughput.
• Virtual links cannot compete with dedicated links
  QoS

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How the Proxy works

• Either return the true IP address of fake IP
  address
• For fake IP address, the packets can be forwarded
  to the nearest VT node
• The VT node can do whatever it wants with the
  packet.
• At the boundary of VT,
• VT egress node, reconverts the packet into
  Internet format for delivery to the server
• Similar to NAT

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Drawbacks of VT

• Cannot control the Quality of Service of packets
  traversing the virtual testbed.
• However, we assume
• Routing and Addressing that more urgently warrant
  attention and for which the virtual test bed
  approach is well-suited

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Related works

• Part of the idea is not new
• X-bone
• Suite of tools supports automated establishment
  and management of overlays.
• Virtual Internet VI
• Allows multiple levels of virtualization
• But, it is closely tie to the current Internet
  architecture
• But different emphasis
• The focus on the VT is on the virtualization of
  overlay nodes themselves. X-bone vs. VT
• Aim at new architecture design. VI vs. VT

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Future Plan for VT

• To Include a high performance backbone
• High-speed backbone with PlanetLab has two major
  advantages
• PlanetLab-based overlays serve as an access
  network for the backbone bring real traffic
• Developing and deploying the hardware does not
  gate the architectural work.

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Deployment

• Old story (discredited) next generation
  architecture -gt validation -gt magic -gt adopted by
  ISPs, router vendors
• Our strategy NGSP has new architecture -gt
  overlay supporting it, proxy software gt
  backwards compatible
• If successful, NGSP offers direct access, or
  competitors start adopting

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Deployment

• Overlays as opportunity to radically change
  architecture instead of merely providing limited
  enhancements

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Deployment

• New architecture could be supported natively
• Single NGSP or long-running virtual testbed
• Successful -gt attract more users -gt architecture
  migrates from virtual testbed to dedicated
• Instead of single architectural winner, might be
  large number of narrowly targeted overlays
• Prevent chaos -gt coordination

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Virtualization Means or Ends

• Virtual testbed approach uses virtualization
• Overlay is qualitatively equivalent to native
  network, users freed from local ISP, network
  providers dont need to deploy new functionality
  at every node
• Many virtual testbeds running simultaneously,
  reduced barrier-to-entry

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Virtualization Means or Ends

• Means
• Architectural changes are rare
• Purist view
• Virtualization is means for architectural change
• Architecture must have flexibility

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Virtualization Means or Ends

• Ends
• Internet changes constantly, with many coexisting
  components
• Pluralist view
• Virtualization is crucial to support many
  components and constant change
• Flexibility is in adding or augmenting overlays

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Virtualization Means or Ends

• Dont know which is correct, but our approach
  lets us find out

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Conclusions

• If new architecture is promising, ISPs, router
  vendors will adopt
• No longer true, so researchers narrowed their
  focus -gt empirical or incremental studies -gt
  insufficient to meet new Internet requirements
• Through virtual testbeds, hopefully there will be
  new research unrestricted to incremental designs
• Through new deployment strategy closer to
  experimental methodology, raise sights of
  researchers

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Oasis An Overlay-Aware Network Stack

• Harsha V. Madhyastha, Arun Venkataramani, Arvind
  Krishnamurthy, and Thomas Anderson
• University of Washington and University of
  Massachusetts Amherst